Chemicals are commonly used in a variety of agricultural applications as, for example, terrestrial or aquatic herbicides, growth regulators, antidotes, harvest aids and the like. A defoliant is one such harvest aid and is applied to a crop prior to harvest to promote earlier maturity, reduce bruising, minimize trash and generally enhance crop harvestability and enhance quality of the harvested crop.
An agriculturally acceptable defoliant facilitates leaf drop by accelerating the formation of the abcission layer at the leaf axil but does not affect other abcission layers such as those at the base of bolls or other fruiting bodies. An effective defoliant will cause plants to drop their leaves and will not simply dry or shrivel the leaves since undropped, albeit dried or shriveled, leaves cause harvesting problems, i.e., excess trash in the harvested crop, that increases harvesting, storage and processing costs.
A defoliant must be fast working and be effective over a wide range of climatic conditions and should also be "weather fast", i.e., not significantly affected by precipitation. Also a defoliant must be nontoxic, biodegradable and leave no residue on the fruiting body or the soil. In addition, the maturing process or the quality of the fruiting body must not be adversely affected.